The prevalence of pediatric obesity has increased significantly and approximately 11 percent of American children and adolescents are obese. Of particular concern, the greatest increase in prevalence has occurred among the heaviest medical and psychosocial morbidity than milder obesity is. Moreover, severely obese children are likelier than less severely obese children are to be become obese adults and suffer the long term health consequences of obesity. Although the efficacy of family based behavioral weight control programs in the treatment of moderate pediatric obesity is well established, few studies have focused on the treatment of severe obesity. Thus in this application, we propose a randomized controlled trial to evaluate the efficacy of a family-based behavioral weight control program in the management of severe pediatric obesity. Two hundred children aged 8-12 will be randomized to a 6-month family-based program or usual care, and will complete assessments at pre- and post-treatment and 6 month and 12 month follow-ups. It is hypothesized that: Children who participate in the family based program, when compared to children who receive usual care, will report symptoms. A secondary aim of the proposed investigation is to examine the relationships among gender, race, compliance to diet and exercise, level of parent adherence and treatment outcome. The proposed investigation will gather data about a serious public health problem and establish a foundation for programmatic research to develop effective treatments for an underserved population.